diff options
| -rw-r--r-- | Documentation/block/queue-sysfs.txt | 10 | ||||
| -rw-r--r-- | block/blk-settings.c | 4 | ||||
| -rw-r--r-- | block/blk-sysfs.c | 40 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 1 |
4 files changed, 53 insertions, 2 deletions
diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt index 3a29f8914df9..e5d914845be6 100644 --- a/Documentation/block/queue-sysfs.txt +++ b/Documentation/block/queue-sysfs.txt @@ -20,7 +20,7 @@ This shows the size of internal allocation of the device in bytes, if reported by the device. A value of '0' means device does not support the discard functionality. -discard_max_bytes (RO) +discard_max_hw_bytes (RO) ---------------------- Devices that support discard functionality may have internal limits on the number of bytes that can be trimmed or unmapped in a single operation. @@ -29,6 +29,14 @@ number of bytes that can be discarded in a single operation. Discard requests issued to the device must not exceed this limit. A discard_max_bytes value of 0 means that the device does not support discard functionality. +discard_max_bytes (RW) +---------------------- +While discard_max_hw_bytes is the hardware limit for the device, this +setting is the software limit. Some devices exhibit large latencies when +large discards are issued, setting this value lower will make Linux issue +smaller discards and potentially help reduce latencies induced by large +discard operations. + discard_zeroes_data (RO) ------------------------ When read, this file will show if the discarded block are zeroed by the diff --git a/block/blk-settings.c b/block/blk-settings.c index 12600bfffca9..b38d8d723276 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -116,6 +116,7 @@ void blk_set_default_limits(struct queue_limits *lim) lim->chunk_sectors = 0; lim->max_write_same_sectors = 0; lim->max_discard_sectors = 0; + lim->max_hw_discard_sectors = 0; lim->discard_granularity = 0; lim->discard_alignment = 0; lim->discard_misaligned = 0; @@ -303,6 +304,7 @@ EXPORT_SYMBOL(blk_queue_chunk_sectors); void blk_queue_max_discard_sectors(struct request_queue *q, unsigned int max_discard_sectors) { + q->limits.max_hw_discard_sectors = max_discard_sectors; q->limits.max_discard_sectors = max_discard_sectors; } EXPORT_SYMBOL(blk_queue_max_discard_sectors); @@ -641,6 +643,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->max_discard_sectors = min_not_zero(t->max_discard_sectors, b->max_discard_sectors); + t->max_hw_discard_sectors = min_not_zero(t->max_hw_discard_sectors, + b->max_hw_discard_sectors); t->discard_granularity = max(t->discard_granularity, b->discard_granularity); t->discard_alignment = lcm_not_zero(t->discard_alignment, alignment) % diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 6264b382d4d1..b1f34e463c0f 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -145,12 +145,43 @@ static ssize_t queue_discard_granularity_show(struct request_queue *q, char *pag return queue_var_show(q->limits.discard_granularity, page); } +static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page) +{ + unsigned long long val; + + val = q->limits.max_hw_discard_sectors << 9; + return sprintf(page, "%llu\n", val); +} + static ssize_t queue_discard_max_show(struct request_queue *q, char *page) { return sprintf(page, "%llu\n", (unsigned long long)q->limits.max_discard_sectors << 9); } +static ssize_t queue_discard_max_store(struct request_queue *q, + const char *page, size_t count) +{ + unsigned long max_discard; + ssize_t ret = queue_var_store(&max_discard, page, count); + + if (ret < 0) + return ret; + + if (max_discard & (q->limits.discard_granularity - 1)) + return -EINVAL; + + max_discard >>= 9; + if (max_discard > UINT_MAX) + return -EINVAL; + + if (max_discard > q->limits.max_hw_discard_sectors) + max_discard = q->limits.max_hw_discard_sectors; + + q->limits.max_discard_sectors = max_discard; + return ret; +} + static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page) { return queue_var_show(queue_discard_zeroes_data(q), page); @@ -360,9 +391,15 @@ static struct queue_sysfs_entry queue_discard_granularity_entry = { .show = queue_discard_granularity_show, }; +static struct queue_sysfs_entry queue_discard_max_hw_entry = { + .attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO }, + .show = queue_discard_max_hw_show, +}; + static struct queue_sysfs_entry queue_discard_max_entry = { - .attr = {.name = "discard_max_bytes", .mode = S_IRUGO }, + .attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR }, .show = queue_discard_max_show, + .store = queue_discard_max_store, }; static struct queue_sysfs_entry queue_discard_zeroes_data_entry = { @@ -421,6 +458,7 @@ static struct attribute *default_attrs[] = { &queue_io_opt_entry.attr, &queue_discard_granularity_entry.attr, &queue_discard_max_entry.attr, + &queue_discard_max_hw_entry.attr, &queue_discard_zeroes_data_entry.attr, &queue_write_same_max_entry.attr, &queue_nonrot_entry.attr, diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index d4068c17d0df..243f29e779ec 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -268,6 +268,7 @@ struct queue_limits { unsigned int io_min; unsigned int io_opt; unsigned int max_discard_sectors; + unsigned int max_hw_discard_sectors; unsigned int max_write_same_sectors; unsigned int discard_granularity; unsigned int discard_alignment; |